Influence of sage seed gum on some physicochemical and rheological properties of wheat starch

Abstract

The effect of sage seed gum at different concentrations (0, 0.1, 0.25, and 0.5% w/w) on swelling power, solubility index, paste clarity, and steady shear flow behavior of wheat starch dispersion (2%, w/w) was evaluated. Sage seed gum addition enhanced the swelling power at all temperatures chosen (50–90°C). It also increased leakage of starch polymers at temperatures <80°C. In contrast, this addition decreased the activation energy needed for swelling (up to 34.17%) and solubilization (up to 30.85%). The paste clarity of wheat starch significantly decreased in the presence of SSG (p < 0.05). The apparent viscosity increased with the increasing SSG concentration and all the samples exhibited shear thinning flow behavior. Among the rheological model used, Sisko's model fitted well to the experimental data (R2 = 0.988–0.999, RMSE = 0.001–0.0018). Accordingly, addition of sage seed gum up to 0.5% resulted in an approximately twofold increase in η∞, 251‐fold in ks, but a 19% decrease in ns values of wheat starch dispersion. The concentration dependence of the apparent viscosity at a shear rate range of 10–100 s−1 was also analyzed using well‐defined models.